Ah, here we have another problem! DAB can't be ordered with the RNS 510 but the SEAT Media System 2.2 has bluetooth and DAB as standard (RNS 315). There are so many anomalies with the head units and all of them can work with all models with a bit of coding but can't actually be ordered with all models in this country if you follow me. In Germany you can probably order one of about half a dozen headunits!
I think that is why your car perhaps doesn't have bluetooth, as I'm not sure you can spec bluetooth and DAB together (plus Dynaudio) as there are only so many connections on the back of the unit.
Unfortunately the RNS 315 doesn't have the big hard drive that the RNS 510 has and from memory takes it's stuff from an SD card or CD/DVD. I'm not sure it can play movies.
There are OEM looking units from some of the big brands that have nearly all of the features of the RNS 510 plus maybe bluetooth built in but I'm not sure if they will have the DAB. It's so hard to keep up with this stuff as there's new things being introduced every couple of months. There are also a lot of Chinese OEM looking head units that have all sorts of features.
You can get rips of the latest maps and speed camera POIs online for not much money.